1. Field of the Invention
The present invention relates to a so-called outdoor, portable gas lantern, and more particularly, to a structure for supporting a globe which is one of structural components of a portable gas lantern.
2. Description of the Related Art
FIG. 1 shows an example of a conventional portable gas lantern known in the prior art. In FIG. 1, a portable gas lantern 10 is comprised of a gas cartridge 11 containing compressed combustible gas and a gas burner 12 that can freely be attached to and detached from the gas cartridge 11. The gas cartridge 11 and the gas burner 12 are assembled in a hermetically sealed state by a gasket 13.
The gas burner 12 is connected to the gas cartridge 11, and the connection is comprised of a plug fitting 14 through which combustible gas supplied from the gas cartridge 11 passes, a knob 15 connected to a gas flow adjusting spindle that adjusts the flow rate of the combustible gas passing through the plug fitting 14 by controlling the degree of opening of a gas passage formed in the plug fitting 14, a burner head 16 with a number of openings 16a penetrating the surface of the head, a mixing tube 17 connecting the plug fitting 14 to the burner head 16, an ignition electrode 18 for igniting a gas mixture of air and the combustible gas flowing in the mixing tube 17, and an ignition button 19 installed on the plug fitting 14 for actuating the ignition electrode 18.
In addition, an approximately hemispherical globe supporter 20 is mounted on the mixing tube 17, for installing a globe, and a globe 21 that is shaped substantially as a cylinder is engaged with the globe supporter 20. The globe 21 is open at both the upper and lower ends, and is composed of a transparent material such as transparent glass or frosted glass. A ventilator 22 is mounted at the top of the globe 21, so that the ventilator covers the top of the opening of the globe 21.
This portable gas lantern 10 is operated as follows.
First, a substantially spherical light emitting body (not illustrated) called a mantle is installed to cover the burner head 16, before the gas lantern 10 is used.
A combustible gas in a pressurized state enters into the plug fitting 14 from the gas cartridge 11, and is fed into the mixing tube 17 while the knob 15 connected to the gas flow adjusting spindle controls the gas flow. The mixing tube 17 is provided with an opening 17a through which external air is taken into the mixing tube 17 by a negative pressure produced when the combustible gas passes through the interior of the mixing tube 17. The combustible gas is mixed with air entering through the opening 17a, to produce a gas mixture of the combustible gas and air.
When the user of the lantern presses the ignition button 19 after the gas mixture enters the burner head 16, a spark discharge occurs between the ignition electrode 18 charged positively and the mixing tube 17 charged negatively, and the spark ignites the gas mixture flowing in the mixing tube 17 through the opening 17a. In this way, the ignited gas mixture flows out through a number of openings 16a formed in the surface of the burner head 16, so as to illuminate the mantle installed around the burner head 16.
As described above, the light emitting body (mantle) is illuminated by the burning combustible gas, and the gas lantern 10 can be used as a light source outdoors, for instance.
As shown in FIG. 1, the globe 21 is mounted on the globe supporter 20 by a pair of globe mounting springs 23, and the globe 21 can be freely attached to and removed from the globe supporter.
The globe mounting springs 23 are comprised of leaf springs shaped in a crank, and one end 23a is fixed to the inner wall of the globe supporter 20. The other end 23b is structured as a free end, and the globe 21 is supported by the globe supporter 20 because the free end 23b presses the inner wall of the globe 21 in an outward direction. The crank portion 23c of the globe mounting spring 23 is located outside the globe supporter 20. When the upper and lower surfaces of the crank portion 23c are pressed together, the free end 23b of the globe mounting spring 23 rotates around the crank portion 23c, and engagement between the free end 23b and the inner wall of the globe 21 is released, and as a result, the globe 21 can be removed from the globe supporter 20.
A number of arc-shaped springs 24 are provided at the bottom of the ventilator 22. The springs 24 extend outwards from the ventilator 22, enter the interior of the globe 21 through the top surface of the opening of the globe 21, and engage with the inner wall of the globe 21. Thus arranged, the ventilator 22 is supported by the globe 21.
As described above, the globe 21 is supported by the globe supporter 20 as the globe mounting springs 23 press on the inner wall of the globe 21. When the globe 21 is to be removed from the globe supporter 20, the globe mounting springs 23 do not interfere with the removal of the globe 21 because the crank portions 23c have been pressed and the springs have been rotated inwards from the globe 21, so the springs do not obstruct the removal of the globe 21.
When the globe 21 is reinstalled onto the globe supporter 20 after being once removed, the upper and lower surfaces of the crank portion 23c is pressed from both upper and lower surfaces, and while the globe mounting springs 23 are rotated inwards relative to the globe 21, the globe 21 is mounted on the globe supporter 20, and thereafter pressure on the crank portion 23c is released, so that the free ends 23b of the globe mounting springs 23 contact the inner wall of the globe 21.
At this time, if the pressure on the crank portion 23c is released instantaneously, the free ends 23b of the globe mounting springs 23 are acted upon by the whole spring force which was accumulated by the rotation of the globe mounting springs 23, therefore the inner wall of the globe 21 is instantaneously impacted by the free ends 23b of the globe mounting springs 23 with an extremely large force. Unfortunately, the globe 21 has been manufactured with a thin wall to give a high transmission of light. As a consequence of these factors, the globe 21 has often been cracked by the globe mounting springs 23 when the globe 21 was mounted on the globe supporter 20.
Therefore, when a consumable component, the mantle, is to be replaced in a conventional gas lantern 10 known in the prior art, the mantle cannot be replaced unless the globe 21 is removed, so there is the inconvenience of preparing a spare globe 21 at any time to cope with the breakage of the globe 21.
In addition, the ventilator 22 is also installed at the opening of the globe 21 by the springs 24 pressing on the inner wall of the top of the globe 21. Therefore, also when the ventilator 22 was removed from the globe 21, the same problem as above used to occur. In other words, because the ventilator 22 engages with the globe 21 with a large spring force, the globe 21 with a thin wall often cracks if an attempt is made to withdraw the ventilator 22 from the globe 21 with excessive force.
Furthermore, with the conventional gas lantern 10 shown in FIG. 1 as known in the art, the ventilator 22 and the globe supporter 20 are separately attached to the globe 21, so even if an attempt is made to remove the globe 21 only to clean off soot adhering to the inner wall of the globe 21, two removal operations must be performed; removal of the ventilator 22 from the globe 21, and removal of the globe 21 from the globe supporter 20.